The present invention concerns a development to elapsed time indicators of the type used in conjunction with electrically operated equipment to log running time and also with event counters.
Non-volatile semiconductors can store data without an electrical input like a battery for many years and this attribute had led to the development of electronic identification systems (EID) which are effectively electronic bar codes.
Additionally, because non-volatile semiconductors can be programmed by providing a suitable electrical bias, the data can be changed and still remain nonvolatile after each changexe2x80x94the so-called electrically alterable read only memory (EAROM). This has enabled several applications, including the storage and indication of the running time of equipment (so-called elapsed time indicators) or the on equipment logging of data on maintenance/asset tracking.
An aim of the present invention is to provide an improved means of logging data concerning an item of equipment.
In accordance with the present invention, there is an elapsed time and data indicator comprising a non-volatile memory, control circuitry by which data can be read from and written to the memory, a timer, means for connection to the electrical supply of a host apparatus, and an interface through which data can be exchanged with the memory, such that in use the timer measures the duration of periods during which the host electrical supply is switched on and in dependence on the timer output the control circuitry maintains a cumulative record of elapsed host apparatus running time which is stored on the non-volatile memory, other data relating to the host apparatus being writable to the non-volatile memory so that the indicator can be used to record and, through the interface, supply elapsed host apparatus running time in conjunction with other data relating to the host apparatus.
In a broader aspect, the data indicator of the present invention comprises a non-volatile memory, control circuitry by which data can be read from and written to the memory, means for connection to the electrical supply of a host apparatus, a detector connected to the means for connection to the electrical supply of the host apparatus, and an interface through which data can be exchanged with the memory, such that in use the detector detects when the host electrical supply is switched on and in dependence on the detector output the control circuitry maintains a cumulative history of host apparatus activation which is stored on the non-volatile memory, other data relating to the host apparatus being writable to the non-volatile memory so that the indicator can be used to record and, through the interface, supply elapsed host apparatus activation data in conjunction with other data relating to the host apparatus.
By making available the running time or number of times the equipment has been used in conjunction with other data, the apparatus in accordance with the invention opens up a host of advantageous possibilities, especially with regard to logistics/asset management and reliability monitoring.
For instance, the data may include the timing of previous service(s) so that taking account of the total elapsed time recorded by the indicator an indication of whether a service is due, or of how much running time remains before the next service, may be provided. Relevant data such as the service interval could also be stored by the indicator.
The data storable on the indicator will typically include a host apparatus identifier. It may also include other logging data. This may comprise one or more of: maintenance data, tracking data, reliability data (fault data), modification level.
The indicator is preferably formed as a single unit comprising a housing containing the circuitry, means for mounting the housing to the host apparatus, terminations for connection of the circuitry to the host electrical supply and a contact or contacts connected to the interface and through which a connection can be releasably made to means for interrogating the indicator.
Such a unit may be retro-fittable to an existing apparatus. It need not necessarily have means for displaying the stored data. This can be more economically achieved using an additional device connected to the indicator through the contacts. For example, the means for interrogating the indicator may comprise a computer connectable to the indicator through a plug engageable with the contacts. The computer can be used to receive data from any number of indicators.
The circuitry of the indicator may be arranged to draw its power supply from the host apparatus via the means for connection to the host electrical supply. In this way, batteries or other maintenance requiring dedicated power source can be dispensed with.
It is particularly preferred that a separate device for receiving and displaying the stored data is additionally provided comprising a power supply, means for connection to the indicator such as to supply power and receive the data therefrom, and means for displaying received data. A battery is a suitable power supply. Such a device can be conveniently used to interrogate the indicator even when it is not receiving power from the host. It may be configured to clip onto the indicator for convenience. The means for data display may utilise a liquid crystal display.